A DISSERTATION SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN TROPICAL ANIMAL PRODUCTION OF SOKOINE UNIVERSITY OF AGRICULTURE. MOROGORO, TANZANIA.The study was carried out at Fuoni Village in Magharibi ‘B’ District of Zanzibar for period of six weeks, to evaluate the potential of using fish guts in broiler chicken diets. The two hundred and forty broiler chicks were used in four dietary treatments. Each treatment contained 60 chicks which were randomly allocated into four brooding pens and each treatment was replicated 3 times with 20 chicks each. Weight of feeds and refusal were measured daily whereas chick body weight was measured once per week. The DM intake was significantly (P < 0.05) higher for the birds fed diets containing 0% and 40% fish guts during the 2nd and 5th week of age, where as no significant differences were observed during the other weeks. There was significant effect (P < 0.05) for average feed conversion ratio and it was higher for birds fed diets containing 40% and 60% fish guts. The observed body weight and average daily gain were significantly (P < 0.05) heavier in birds fed diets 0% and 20% fish guts. However, no significant differences (P > 0.05) were observed for carcass weight, dressing percentage, meat tenderness and cooking loss between the four dietary treatments. The results on the chemical composition of meat showed that there was no significant (P >0.05) effect for percentage dry matter, crude protein and ash content while ether extract was highly significant (P < 0.05) in the meat of birds fed diets containing 40% and 60% fish guts. The study revealed that feed cost was low for diets containing 60% fish guts being Tshs 649.7 per bird while gross margin of Tshs 349.5 per bird was higher than control diet. The present study showed that 20% fish guts is an optimum level to replace fish meals in broiler diets without affecting performance significantly.